There is a need in the trucking industry for a safe and easy to operate mechanism for holding the trailer door in the open position while cargo is being handled. Such a device must be compatible with both side and rear loading trailers and capable of operating efficiently with sliding, folding, and rolling type doors. The latching mechanism must be simple and quick to operate from outside the trailer as opposed to from inside or underneath the trailer. Furthermore, the latching device must not create unsightly, interfering, and unlawful protrusions of components beyond the normal dimensional characteristics of the trailer.
The most common door securing device which is used on truck trailers or semi-trailers is a simple hook and eye mechanism for holding the trailer doors in an open position. In order for the hook and eye device to practically operate, any type door using it must have sufficient play that the door is capable of some movement even when latched. This allows the hook and eye to be engaged or disengaged. These hook and eye devices have several problems which render them both inefficient and dangerous. In these simple devices, the hook is frequently jarred from the eye by sudden movement of the trailer during loading or unloading. The trailer can be moved sufficiently to cause this undersirable result from the shifting of cargo, from a lift truck or worker boarding or unboarding, or simply from the wind. Even if the jarring force is not of sufficient magnitude to disengage the hook and eye directly, a sufficient momentum can be built up due to the play necessary for originally engaging the hook and eye that shears the hook portion of the hook and eye device. If the hook is sheared or the door is otherwise unexpectedly released, it has a tendency to return to the closed position. When the door is unexpectedly and suddenly returned to the closed position, personal injury or damage to property may result. Workers can be struck and seriously injured when a hook disengages the eye and the heavy trailer door closes upon them. Workers can have their arms or hands pinched or crushed when attempting to latch or unlatch the hook because this activity requires that the worker place his hand and arm between the heavy trailer door and the side of the trailer thereby exposing the worker to the danger of being pinned between door and trailer.
In addition to the possible personal injuries, equipment can be extensively damaged if it is struck by a released door during the loading or unloading of cargo. The cargo itself may be damaged or destroyed by colliding with an unlatched door. Additionally, whenever an accident occurs incident to the trailer door swinging shut, time is lost in attending to injuries, making repairs, or replacing damaged goods or equipment. Of course, the loss of time is expensive and the potential of injury is demoralizing to a crew of workers.
The present invention cures the safety deficiencies of the hook and eye latching devices, and has several other desirable features. The latching device of this invention provides a positive latch that eliminates the play between the door and the latching mechanism when the door is being held in the open position. The latching device of the present invention withstands shearing forces, and it does not disengage when the truck is jarred during loading or unloading. The device of this invention does not require that the user expose himself to danger while engaging or disengaging the latching mechanism.
It is an object of the present invention to provide a latching device for securing doors in an open position which is simply and quickly operated.
A further object of the present invention is to provide a positive latching mechanism that remains latched when inadvertently jarred.
Another object of the present invention is to provide a positive latching device able to withstand shearing forces.
An additional object of the present invention is to provide a positive latching device that is safely operated from outside the trailer rather than from inside, underneath, or between parts of the truck trailer.
Still another object of the present invention is to provide a positive latching device that does not excessively or unlawfully protrude from the normal dimensional characteristics of a truck trailer or interfere with operation of the trailer, loading, or unloading.
Finally, an object of the present invention is to provide a positive latching device compatible for use on all types of trailer doors which is simple and relatively inexpensive to construct or manufacture and easy to install.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appending claims, and upon reference to the accompanying drawings.